A threatening message was found on the property of a prestigious North Jersey private school this week. The message was discovered on the grounds of the Dwight-Englewood School in Englewood on Monday night, according to a statement from the school. Students were on a break for the Passover holiday when the message was found and were scheduled to return on Wednesday. Administrators decided to close the school for an additional day as the incident was investigated by law enforcement. The school will operate on a normal schedule on Thursday. The Englewood Police Department, which is leading the i…